Prosthetic lenses and methods of making the same

ABSTRACT

Aspects of the disclosure provide for a method of creating a lens. Examples of the method include identifying a limbal zone of the eye, determining a back optic zone within the limbal zone, determining a front optic zone based at least partially on the limbal zone, computing a lens surface of the lens based at least partially on the limbal zone, the back optic zone, and the front optic zone, de-centering at least one of the back optic zone or the front optic zone from a visual axis or a spindle axis of the lens.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 62/622,624, which was filed Jan. 26, 2018, and is titled“Prosthetic Lenses and Methods of Making the Same,” is acontinuation-in-part of, and claims priority to, U.S. patent applicationSer. No. 15/367,970, which was filed Dec. 2, 2016, now U.S. Pat. No.10,534,197, and is titled “Prosthetic Lenses and Methods of Making theSame,” which is a continuation-in-part of U.S. patent application Ser.No. 14/187,036, which was filed Feb. 21, 2014 and now granted as U.S.Pat. No. 9,551,885 on Jan. 24, 2017, and is titled “Prosthetic Lensesand Methods of Making the Same,” which claims priority to U.S.Provisional Patent Application No. 61/928,351, which was filed Jan. 16,2014, and is titled “Prosthetic Lenses and Methods of Making the Same,”and U.S. Provisional Patent Application No. 61/740,834, which was filedDec. 21, 2012, and is titled “Prosthetic Lenses and Methods of Makingthe Same,” all of which are hereby incorporated herein by reference intheir entireties.

BACKGROUND

In the past (more than 50 years ago), impression molding was done on theeye using a plaster-like substance. A “positive” image was made from themold using more plaster. A lens was then created by vacuum sealingplastic to the positive mold. A significant amount of time was thenspent in post processing of the optics and fit adjustments. The lens didnot breathe oxygen and could not be worn very long. In addition, therewere problems with this process including shrinking of the mold as itdried, which created a shape very different from the actual eye. Currentbreathable plastics cannot be vacuum molded.

All contact lens designs currently utilize a series of curves, whichapproximate the average ocular surface. There are no contact lensescustom fit based on the actual surface of the eye. At this time, allocular surface evaluation data comes from expensive digital imageryequipment and gives information on a limited surface area, requiringextrapolations of curvatures and prevents customized micro-changes ofthe posterior contact lens surface.

Scleral contact lenses (large diameter lenses) comprise a subset of gaspermeable (GP) contact lenses and completely vault the cornea, landinginstead on the scleral part of the eye. Although the original glassscleral contact lenses were first fit in the 1930s, and later moldedplastic scleral lenses on the 1950s and 1960s, it was not until the late1990s that material advancements made their clinical use practical andphysiologically tolerable.

Currently available scleral lens are at best semi-custom, and requiresubjects to sit for extended fitting sessions performed by specializedcontact lens eye care providers. Many who suffer from corneal and ocularsurface disease are not located near a specialist and incur pricey andrepeated travel expenses. These factors are barriers for subjects withcorneal disease, and many reach a point where treatment options andvisual corrections become very limited.

There is a significant need for a highly customizableoxygen-transmitting device, which follows the contours of an individualeye.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and theadvantages thereof, reference is now made to the following briefdescription, taken in connection with the accompanying drawings anddetailed description:

FIG. 1 is a flowchart of a method of providing a lens according to anembodiment.

FIGS. 2A-2C are various views of an embodiment of a tray.

FIG. 3 is a flowchart of a method for obtaining an impression of asubject's eye according to an embodiment.

FIG. 4 is a flowchart of a method for designing a lens according to anembodiment.

FIGS. 5A and 5B are schematic diagrams of a tray and a lens according toan embodiment.

FIG. 6A illustrates a view of a lens having a regular non-symmetrichyperbolic paraboloid shape positioned over an eye according to anembodiment.

FIG. 6B illustrates a view of a lens having an irregular non-symmetricshape positioned over an eye according to an embodiment.

FIG. 7 illustrates a side view of a lens having de-coupled optic zonespositioned over an eye according to an embodiment.

FIG. 8 illustrates an exemplary computer system suitable forimplementing the several embodiments of the disclosure.

DETAILED DESCRIPTION

In the drawings and description that follow, like parts are typicallymarked throughout the specification and drawings with the same referencenumerals, respectively. In addition, similar reference numerals mayrefer to similar components in different embodiments disclosed herein.The drawing figures are not necessarily to scale. Certain features ofthe invention may be shown exaggerated in scale or in somewhat schematicform and some details of conventional elements may not be shown in theinterest of clarity and conciseness. The present invention issusceptible to embodiments of different forms. Specific embodiments aredescribed in detail and are shown in the drawings, with theunderstanding that the present disclosure is not intended to limit theinvention to the embodiments illustrated and described herein. It is tobe fully recognized that the different teachings of the embodimentsdiscussed herein may be employed separately or in any suitablecombination to produce desired results.

The purpose of the disclosed embodiments is to provide the best qualityof life, through vision, for subjects who are extremely visuallyimpaired and currently without alternative solutions to their cornealdisease. The disclosed embodiments are indicated for keratoconus,irregular astigmatism, ocular surface disease (dry eye), trauma, extremecases of deformed eyes, pellucid marginal degeneration, chemical burns,post-surgical corneas (including corneal transplants and postLaser-Assisted in situ Keratomileusis (LASIK) ectasia), pinguecula,pterygium, stem cell failure, or simply those who desire better visionand comfort. The disclosed embodiments include a prosthetic scleralcover shell, which improves vision by creating a new, smooth, refractivesurface for the eye. The lenses produced by the disclosed embodiments,like fingerprints, are unique to each individual.

As shown in FIG. 1, a process for producing a device or lens isillustrated in a flow chart, and each step is described in more detailherein. As used herein, the “device” or “lens” can refer to a prostheticscleral optical shell with optical qualities, as well as any other typeof lens that contacts the eye, such as a retinal contact lens.Initially, an impression of a subject's eye can be obtained at step 102.In an embodiment, the EyePrint Impression Process can be used to obtainthe impression of the eye. The EyePrint Impression Process is relativelysimple process that only takes a few minutes to captures the curvaturesof the entire eye surface using an impression. This comfortable andgentle process gives more information than high tech computerizedtopographical scanners and gives doctors the ability to fit complicatedpatients with precision. The EyePrint Process resulting in the patientspecific impression provides details of ocular surface never recognizedbefore in lens design.

Once the impression is obtained, a custom lens can be designed using theimpression in step 104. After obtaining the impression, the impression(e.g., the EyePrint Impression) can be shipped to a vendor (e.g.,EyePrint Prosthetics LLC) for digitizing and prosthetic scleral covershell design. Through the latest technology in three-dimensional (3D)scanning and computer controlled machining systems, a match can beachieved to each individual cornea and sclera on a micrometer (i.e., a“micron”) scale. Once the lens is designed, it can be manufactured instep 106 and subsequently dispensed to the subject in step 108. Sincethe lenses disclosed herein can be manufactured using high oxygenpermeability material with high quality optics, the wearers can obtainthe best in comfort, health, and vision.

In at least some exemplary implementations of method 100, step 102 isomitted and instead digital information pertaining to the subject's eyeis instead provided to a vendor for designing the custom lens. Thedigital information may be elevation specific data of the subject's eye,such as measured by an ocular coherence tomographer or other measurementdevice. In other examples, the digital information may be data pointsresulting from a 3D scanning of an impression, data points resultingfrom a 3D scanning of the subject's eye, or any other suitable datapoints that provide sufficient detail regarding elevation and surfacecharacteristics of the subject's eye to enable the vendor to design thecustom lens.

In yet other exemplary implementations of method 100, neither theimpression, nor digital information pertaining to the subject's eye, areprovided to a vendor and instead a physician who made the impressionand/or captured the digital information instead designs the custom lens,for example, using one or more software applications provided by avendor.

The process of taking an ocular impression and then virtual fittingallows a low tech, low cost, simple way for highly complex lenses to befit by local providers. Recent development of highly oxygen permeablelens materials and a new generation of computer driven lathes maketaking a low-tech ocular surface impression to a high tech prostheticscleral shell possible. Impression materials may include vinylpolysiloxane (VPS), which is also referred to in some contexts aspolyvinyl siloxane, or other similar materials known in the art, such asdental impression materials, to create a highly accurate impression ofthe ocular surface.

In order to generate the impression, an ocular tray may be used alongwith an impression material. The tray is generally configured to allowthe impression material to be placed in contact with the eye to therebyform an impression of the outer surface of the patient's eye. Ingeneral, any tray suitable for holding an amount of the impressionmaterial in contact with an eye may be used.

As described above, the initial step in the process includes obtainingan impression of a subject's eye. In an embodiment, the impression maybe obtained in a number of ways, including through the use of a tray andimpression compound. An embodiment of a tray 200 is illustrated in FIGS.2A-2C. The tray 200 generally comprises a handle 202, and a bowl 204.The bowl 204 may comprise a sidewall 206 defining an interior volume.The handle 202 can be used to position and retain the bowl 204 inposition during the impression process. The bowl 204 can be used toretain the impression material during the impression process (asdescribed in more detail herein) as well as provide an orientationindication for the impression. In an embodiment, the handle 202 may beoriented along the central axis of the bowl 204 and can be connected atthe apex of the bowl 204. The handle 202 may generally comprise acylindrical shape. An alignment structure or marking may be placed onthe handle to aid in orienting the tray 200 during use. For example, aportion of the handle 202 may be flattened to form a flat side 210. Insome embodiments, other markings such as raised surfaces, visualindicators, and the like can be used to provide an orientation indicatorfor the tray 200.

The bowl 204 may generally comprise a relatively straight sidewall 206.As shown in the cross-sectional depiction in FIG. 2A, the side wall 206may generally be oriented at an angle of between about 60 degrees andabout 120 degrees from each other, although other angles may work aswell. The sidewalls 206 may generally be symmetric about the centralaxis of the bowl 204, thereby defining a conical or frusto-conicalvolume within the bowl. The outer ends of the sidewall 206 may berounded or otherwise smoothed to prevent injuring the eye when the endis placed in contact with the eye. In general, the outer end of the bowl204 may be sized to allow the bowl 204 to be paced in contact with theeye of a subject and cover at least the cornea and a short distance outonto the sclera. For most subjects, the outer end of the bowl 204 maygenerally have a diameter ranging from about 15 millimeters (mm) toabout 30 mm, or about 18 mm to about 28 mm (e.g., 18 mm, 22 mm, 26 mm,etc.), although other sizes may work as well. In some embodiments, aplurality of trays having bowls of different diameters may be availableto allow a suitable size to be selected for a given subject.

As seen from the top view illustrated in FIG. 2B, the outer end of thebowl 204 may define a substantially circular contact surface with theeye. While illustrated as being circular, other round shapes (e.g.,elliptical, oblong, etc.) may also be used. In embodiments, the bowl isconfigured to cover the eye including the optic zone within the limbalcircle as well as at least a short distance beyond the limbal circle.

In some embodiments, the bowl 204 may comprise an alignment structure ormarking. The alignment structure in the bowl 204 may serve to aid inaligning the bowl during the impression process and/or forming a markingin the impression itself for later use during the lens manufacturingprocess. The alignment structure on the bowl 204 may be used in place ofor in addition to the alignment structure on the handle 202. In anembodiment, the alignment structure may comprise a hole or passage 208through the sidewall 206, and the impression material may protrude intoand/or out of the passage 208. When used along with an alignmentstructure or marking on the handle, the passage 208 may be aligned withthe alignment structure on the handle. For example, the passage 208 maybe aligned with the flat surface 210 on the handle to allow for ease ofalignment when using the tray 200.

The tray 200, or one or more portions thereof, may be made from anysuitable material. While opaque materials may be suitable, the use of atransparent or semi-transparent material may help to align the tray onthe eye of the subject during use. For example, the tray 200 may beformed from glass, plastic (e.g., a medium or high impact polymer suchas an acrylic), a composite, or the like.

The tray 200 is configured to retain the impression material. Theimpression material can be configured to be deformable when contactedwith the eye, and the impression material may or may not increase inviscosity after being contacted with the eye. The impression material isgenerally selected to avoid irritation to the eye when placed in contactwith the eye. In some embodiments, the impression material maychemically react to harden or increase in viscosity, thereby “setting”after being contacted with the eye. For example, the impression materialmay be contacted with the eye and left in contact with the eye while thematerial at least partially sets and/or be removed to allow theimpression material to set or continue to set.

In some embodiments, the impression material may comprise a lowviscosity, addition polymerizing material such as a vinyl polysiloxaneimpression material, which has been used in dental work. One suitableimpression material is sold by the trade name Tresident 2000 DHavailable from Schutz Dental GmbH of Germany. The impression materialmay have hydrophilic properties to provide good contact with the eye andthe features on the surface of the eye. When the impression material isconfigured to set, the impression material can be provided as one ormore fluids within a cartridge that can be mixed and injected by auniversal dispenser. The use of a multi-component impression materialmay allow the impression material to be prepared at or near the time theimpression is to be made.

In use, the impression may be obtained using the tray 200. Initially,the subject or patient is prepared for the impression process. Forexample, the subject can be placed in a supine position and asked tofixate on a point (e.g., on a point on a ceiling). If the subject has ahigh refractive error, the subject may use a spectacle trial lens infront of the fixating eye. The subject may generally be made aware ofthe procedure to prepare them for the process.

With reference to FIGS. 2A-2C and FIG. 3, a method 300 of obtaining animpression may begin by selecting a tray 200 at step 302. In general,the tray 200 may be selected to have the largest diameter that caneasily be inserted between the lids of the particular subject. As notedabove, the tray 200 may comprise bowls 204 having a range of sizes, andthe appropriately sized bowl 204 may be selected. The flat edge 210 ofthe handle 202 can correspond to the passage 208 (e.g., a fenestration)of the bowl 204. The passage 208 of the bowl 204 can be placed at the 12o'clock position on the eye. The orientation of the bowl is used togenerate the lens as well as an indication of the orientation of thelens.

The impression material can then be prepared at step 304 and placed inthe bowl at step 306. When the impression material is a singlecomponent, it may be placed in the interior volume of the bowl 204. Whena multi-component impression material is used, it may be mixed andplaced in the bowl 204. For example, when the impression material issupplied as a liquid, multi-component mixture in separate containers orcartridges, the cartridges and impression material may be placed in auniversal dispenser. Any lids or seals may be removed and a small amountof the impression material may be extruded from the cartridges todetermine that the material flows uniformly from both openings. A mixingtip may be used to combine the multi-component impression material as itis extruded from the cartridges. Once the impression material is ready,it may be disposed in the bowl 204. The bowl 204 may be filled so thatthe impression material can contact the eye over the entire surfacedefined by the outer end of the bowl 204.

When an impression material is used that sets, it may be allowed to setfor a short time (e.g., 30 seconds to 2 minutes, or about 60 seconds)before it is ready for use. When the impression material is ready, thetray 200 having the bowl 204 with the impression material within it canbe placed into contact with the subject's eye. In some embodiments, atopical anesthetic may impair the quality of the impression, and as aresult, the impression material may be placed directly in contact withthe eye without any anesthetic being applied.

The bowl 204 may be placed in contact with the eye at step 308. In anembodiment, the bowl 204 may be placed between the eyelids with thealignment passage 208 aligned at the 12 o'clock position. The tray 200can be applied with enough pressure so that the impression materialcompletely rest over the area under the bowl 204. The pressure should beless than an amount that would distort the corneal curvature. Someimpression material may be displaced outside of the bowl 204. Thesubject can fixate on the point to maintain the eye relativelystationary during the impression process. The tray may be maintained incontact with the eye for a time period sufficient to impart theimpression of the eye on the impression material so that the impressionis maintained when the tray is removed. In an embodiment, the bowl maybe maintained in contact with the eye between about 30 seconds and about3 minutes, or about two minutes.

When the impression can be retained by the impression material, the tray200 can be removed from the subject's eye in step 310. In order to breaka seal that may have formed between the impression material and the eye,the bowl 204 may be gently lifted by a single edge while the eye can beindented to break any suction. The bowl and impression material can beconfigured to have a greater bonding strength than the impressionmaterial and the eye. As a result, the impression material shouldgenerally adhere to the bowl 204 rather than the eye when the tray 200is removed, and should not distort when removed from the eye or duringthe curing process. The eye can then be inspected to ensure that theimpression material has been removed and that no injury to the eye hasbeen caused by the impression process. The process may be repeated forthe other eye of the subject if needed. In general, it is expected thatthe impression material can be reused for each eye and/or multiplesubjects.

The impression may be retained within the bowl 204 to allow theimpression to cure or harden further. In general, the impression may bemaintained within the bowl 204 while the impression is sent forscanning, as described in more detail below. A cover or case may be usedto protect the impression in the bowl 204 from damage to the impressionsurface during shipment. In the event that the impression is separatedfrom the bowl 204, the passage 208 (e.g., a fenestration) in the bowl204 may create a marking on the impression to indicate how theimpression is oriented within the eye. For example, the impressionmaterial may displace into the passage 208 during the impressionprocess. If the impression is removed from the bowl 204, a post or tagmay indicate the position of the passage 208 relative to the impression.Other features on the interior of the bowl 204 may also be used toprovide an indication of the orientation of the bowl relative to theeye.

The result of the impression process is a negative impression of theouter surface of the subject's eye formed in the impression material.The use of the impression material may allow for small details of theeye to be captured. Further, the impression material may be selected sothat the impression does not shrink or change dimensions upon setting,thereby providing a high definition representation of the outer surfaceof the eye. Various features of the eye can then be identified in thenegative impression. For example, the negative impression may allow theoptic zone, transition zone, landing zone, and lifting zone to beidentified by representing the limbal circle and/or one or more surfacefeatures (e.g., bumps, indentions, protrusions, irregular shapes, etc.)of the eye, as described in more detail below. The resulting negativeimpression can then be sent for further processing for the scleral covershell to be produced.

The impression can then be used to design and fabricate a lens for thesubject based on the mold. As illustrated in FIG. 4, a method 400 ofdesigning and fabricating the lens may begin by scanning the impressionat step 402. In order to create the lens (e.g., a scleral cover shell),the impression (e.g., a negative mold) of the eye can be scanned into 3Dspace and a file can be created containing a set of 3-dimensional (3D)points (e.g., X, Y, Z coordinates). The scanning can comprise aresolution sufficient to identify the surface features of the eye. In anembodiment, the scan of the eye may have a resolution ranging from about1 micron to about 500 microns, about 4 microns to about 100 microns, orabout 7 microns. In at least some examples, the step 402 is omitted fromthe method 400 and instead the 3D points are directly received, forexample, in digital information provided from another party who scannedthe impression and/or captured the digital information from thesubject's eye, as discussed above with respect to the method 100 of FIG.1.

In some embodiments, the points may be stored in a binary format in astereolithiography (STL) file. The file may be accessible by a suitableapplication such as the applicant's EyePrint Designer Software (EPDS).The application can convert the negative image of the surface of the eyeto a positive image. The application may execute on a processor and canuse an input STL file generated by the 3D scanner. The file can bedisplayed in the 3D space, and various editing tools may be available toprepare the 3D object for the design of the lens.

In some embodiments, the application facilitates designing of the lensusing Elevations Specific Technology. For example, data points obtainedby scanning the impression, or data points received as digitalinformation from a previous scanning of an impression or by directlyscanning or measuring the subject's eye, represent elevation points ofthe subject's eye. In such an example, the application illustrates theelevation points in a color map in which colors are associated with, andrepresentative of, respective heights of the elevation points of thesubject's eye. Based on the color map, in some embodiments, a level ofirregularity is assigned to the subject's eye in total, or to particularzones, regions, or portions of the subject's eye. The level ofirregularity, in some examples, is indicative of, or is related todetermining, a level of difficulty and/or an amount of time required tofabricate the lens after designing.

The application can include an application or a wizard that guides theuser from the selection of the eye mold to the generation of theproduction files, which can be used with a lathe, mill, or 3D printer tocreate the lens. For example, the production files can be used with aComputer Numerically Controlled (CNC) 2-axis lathe with Oscillating ToolTechnology (OTT) and/or a DAC ALM OTT lathe (e.g., available from DACInt. Inc. of Carpinteria, Calif.) to prepare the lens. During thesuccessive steps of the lens design, the mold and both lens surfaces canbe displayed in the 3D space using a 3D viewer that lets the user zoomin and out, rotate, orient the view, and adjust the transparency of thesurfaces that are displayed.

The application generally allows for an identification of the zones ofthe eye and generates a production file that defines the inner and outersurfaces of the lens. The production file can then be used to preparethe lens for the user using one or more production techniques. In orderto illustrate the lens design process, reference is made to FIGS. 5A and5B, which illustrates the various zones and features of the invertedmold 501 (i.e., the positive image of the negative impression) of thecorresponding eye and the lens 500. Specifically, FIG. 5A illustrates apartial cross-sectional, side view of a lens on a mold (which may alsorepresent an eye), and FIG. 5B illustrates a bottom view of the lens onthe mold. The mold 501 can be used to identify several features of theeye including, but not limited to, the limbal circle 504 and/or one ormore surface features. Corresponding zones can be defined including theoptic zone 502, a transition zone 506, a landing zone 508, and an edgelift zone 510. The limbus is considered the border between the corneaand the sclera and can be described by reference to the limbal circle504.

The optic zone 502 represents the area where light enters the eyethrough the cornea and is generally defined as being within the limbalcircle 504. In an embodiment, the optic zone 502 can be defined as beingentirely within the limbus, for example, about 1 mm inside the limbus.Since the border between the cornea and sclera is generally not sharp,the transition zone 506 can be defined to capture the limbal circle 504.In an embodiment, the transition zone 506 may have a width of about 2 mmand encompass about 1 mm inside the limbus to about 1 mm outside thelimbus. In general, the lens 500 will have a clearance from contactingthe cornea within the optic zone 502 and the transition zone 506. The“clearance” refers to the distance between the surface of the eye andthe inner surface of the lens 500. In an embodiment, the lens 500 mayhave a clearance between about 100 microns and about 400 microns fromthe eye (e.g., the cornea) in the optic zone 502. In an embodiment, thelens 500 may have a clearance between about 100 microns and about 400microns from the eye at the border with the optic zone 502 and may betouching the eye at the border with the landing zone 508.

The landing zone 508 is a continuation of the transition zone 506 andcan be defined as a region outside of the transition zone 506. Thelanding zone 508 may include a region in which the lens enters intocontact with the sclera. In an embodiment, the landing zone 508 may havean outer diameter ranging from about 15 mm to about 20 mm, or about 18mm. The edge lift zone 510 is a continuation of the landing zone 508 andmay be tangent to the surface of the eye at the intersection with thelanding zone 508. The edge lift zone 510 may have a clearance from thesclera to allow the lens to be lifted off the eye. In an embodiment, theedge lift zone 510 may have a width of between about 0.25 mm and about1.00 mm, or about 0.5 mm. The edge lift zone 510 may have a clearancefrom the sclera of between about 10 microns and about 50 microns, orabout 25 microns at the outer edge of the edge lift zone 510 and may betouching the eye at the border with the landing zone 508.

Referring to FIG. 4 and FIGS. 5A and 5B, the limbus can be identifiedand localized using the application in the second step 404 of the lensdesign process. Using the application, the user can define at least 3points lying on the limbus. The application can then automaticallydefine a limbal circle 504 based on fitting a circle to the points. Ingeneral, the limbus has a circular shape, which is referred to as thelimbal circle 504. In an embodiment, the application can execute acircular regression algorithm to calculate the circle that best fits tothe identified points. More points can be included on the limbus by theuser to fine-tune the position of the circle. When more than threepoints are present, the distance from the calculated circle and thepoints can be minimized to best fit the circle to the points. Forexample, the sum of the square Euclidian distances between each pointand the circle can be minimized to fit the circle to the points. Theresulting position of the limbus is used to determine the spindle axis,which can be identified as an axis perpendicular to the plane of thecircle and passing through a center point of the circle. In someembodiments, the spindle axis can be offset from the center point of thecircle. In an embodiment, the calculation of the limbal circle 504 mayalso allow the 3-D representation of the mold to be re-oriented if themold is not oriented correctly during the scanning process.

In a third step 406, the user can specify if the optic zone 502 shouldbe centered on the limbus or not. In general, several axes can bedefined for the eye. The optical axis refers to an axis passing throughthe center of the optic zone of the lens. The visual axis refers to aline of site where a beam of light would enter the eye and extend to thephobia on the retina. Finally, the corneal apical axis refers to an axispassing through the geometric center of the dome forming the cornea. Ingeneral, the optical axis of the device and the visual axis should alignto provide the highest quality sight for a subject. When the optic zone502 is centered, the spindle axis as defined by the optic zone 502 mayalign with the optical axis and/or the visual axis. When the opticalaxis is decentered, the axis may be defined independently of the spindleaxis. In the event of decentered optic zone 502, the center of the opticzone 502 can be manually positioned using the 3D viewer, or by manuallyspecifying the distance to the limbus center and the angle. For example,the center of the optic zone 502 can be aligned with the optical axis,the visual axis, and/or the corneal apical axis. The optic zone 502diameter can be calculated based on the distance between the optic zone502 center and the limbus.

Once the optic zone 502 is defined, the application can compute (e.g.,automatically compute) the lens back surface in a fourth step 408, wherethe lens back surface may be defined by four zones. First, the opticzone 502 can be assumed to be a 3D spherical cap. The optic zone 502 canbe represented as a circle in a bottom view that is centered on theoptic zone center (e.g., as defined in the second step above). The opticzone 502 circle may have a size that is sufficient so that the opticzone 502 circle is about 1 mm inside the limbal circle 504. In a sideview, the optic zone 502 can have a circular arc shape, whose radius isapproximately equal to the radius of the cornea. In an embodiment, theoptic zone 502 edge clearance and/or the center clearance can bespecified, and the application can calculate a spherical shapeconforming to the clearances.

In the event of a centered optic zone 502, the inner surface of the lensmay have a clearance of between about 100 microns and about 500 microns,or between about 350 microns and about 450 microns (e.g., about 400microns) above the optic zone center, and the border may also have aclearance of between about 350 microns and about 450 microns (e.g.,about 400 microns) above the cornea. In the event of a decentered opticzone 502, the inner surface of the lens may default to about 400 micronsabove the optic zone border. The radius of the inner surface of the lenscan then be matched to the radius of the cornea, which can determine theclearance of the inner surface of the lens above the center of the opticzone 502. Various checks can be performed to ensure that the clearanceof the inner surface of the lens above the center of the optic zone 502for a decentered optic zone 502 is greater than a minimum clearancethreshold. In an embodiment, the minimum clearance threshold may bebetween about 50 microns and about 150 microns, for example about 100microns. If the clearance between the inner surface of the lens and theouter surface of the eye is below the minimum clearance threshold, theclearances, shape, and location of the optic zone 502 can be altered toallow for the minimum clearance threshold.

Second, the transition zone 506, between the optic zone 502 and thelanding zone 508, is a continuation of the optic zone 502. In a bottomview, the transition zone 506 is represented as a ring shape that iscentered on the spindle axis. The transition zone 506 starts from theoptic zone 502 edge and has an approximate width of about 2 mm (e.g.,starting 1 mm inside the limbus and extending to about 1 mm outside thelimbus). In a side view, the transition zone 506 portion of the lens hasa profile approximated by a polynomial shape that is connected to theoptic zone on the inner side and lands on the sclera on the outer side.At the junction with the optic zone 502, the transition zone 506 has aclearance of about 400 microns, and the transition zone 506 contacts thesclera on the outer edge. Within the transition zone 506, the innersurface of the lens may have a clearance of between about 50 microns andabout 150 microns (e.g., about 100 microns) above the limbal circle stemcells. The clearance above the limbal circle may help avoid anyirritation of the limbal stem cells, which can cause discomfort,inflammation, and/or disease for the subject. The shape of thetransition of the inner surface of the lens from the optic zone 502 tothe transition zone 506 may be softened or rounded to avoid any abruptchanges in the direction of the inner surface of the lens (e.g., firstderivative changes). In an embodiment, the transition may be softened byusing surface computations, setting maximum direction change angles,and/or using a minimum junction blend radius. For example, the shape ofthe transition zone 506 can be computed using Bezier curves to enforcefirst derivative continuity at each junction. The application cancalculate the clearance between the inner surface of the lens and theeye at each point in the transition zone 506. If the inner surface ofthe lens contacts the cornea at any point before reaching the landingzone 510, a warning may be generated and the transition zone diameterand/or clearances can be modified to prevent the lens from contactingthe cornea. In some embodiments, when the clearance between the innersurface of the lens and the eye falls below a minimum clearancethreshold, the shape of the inner surface of the lens in the transitionzone 506 may be divided into two or more consecutive Bezier curves thatsatisfy the continuity at the optic zone 502 and landing zone 508interfaces while allowing for the clearances defined by the minimumclearance threshold(s).

Third, the landing zone 508 is a continuation of the transition zone 506and can be defined as a surface that contacts the eye and aligns withthe sclera supporting the weight of the lens on the eye. In a bottomview, the landing zone 508 is represented as a ring shape that starts atthe outer edge of the transition zone 506 and extends to an outerdiameter of between about 15 mm and about 25 mm, between about 16 mm andabout 20 mm, or about 18 mm. In a side view, the landing zone 508 has anapproximately arcuate shape that lies in contact with the sclera.

Fourth, the lens back surface is completed by an edge lift zone 510 toallow for easy removal and improved comfort. The edge lift zone 510 is acontinuation of the landing zone 508 and comprises a clearance from thesclera to allow the lens to be lifted off the sclera. The lens backsurface in the edge lift zone 510 can be defined by Bezier curves toensure a smooth transition at the landing zone 508 interface and areduced or minimum curvature on the lens outer diameter. In a bottomview, the edge lift zone 510 is represented as a ring shape that startsat the outer edge of the landing zone 508 and has a width between about0.1 mm and about 2 mm, for example, about 0.5 mm. In a side view, theedge lift zone 510 has a circular arc shape. The lens may be tangent to,and in contact with, the sclera at the inner edge of the edge lift zone510, and the lens may transition to a clearance at the outer edge of thelens in the edge lift zone 510. In an embodiment, the lens may have aclearance between about 5 microns and about 50 microns, or between about20 microns and about 100 microns at the outer edge of the lens in theedge lift zone 510.

The lens back surface can be automatically calculated when theclearances and widths are set in the application. Upon calculating thelens back or inner surface, a representation of the inner surface of thelens can be displayed in a 3D viewer. The user can manually tune eachzone clearance and diameter, and see the changes in real time in the 3Dviewer.

The application may raise warnings based on the computed lens backsurface and the surface of the mold 501 in an optional fifth step 410.In an embodiment, the application may determine a clearance between theback of the computed lens and the surface of the mold 501. Warnings canbe generated based on the distance between the inner surface of the lensand the mold either falling under a given minimum clearance threshold orresulting in contact. In an embodiment, clearance ranges may beestablished for the optic zone 502, the transition zone 506, and/or theedge lift zone 510. When the computed clearances between the innersurface of the lens 500 and the mold fall outside of these ranges, theapplication may generate a warning message. Similarly, when the backsurface of the lens touches the mold at one or more designated points,the application may generate a warning message. When a warning messageis generated, the user may redefine the lens shape (e.g., clearances,diameters, etc.) to address the warning so that all of the distancesfall within the established ranges or thresholds.

In a sixth step 412, the user has the possibility to define bumps, i.e.small peaks on the eye needing extra clearance. The process issemi-automated, and the user can adjust the size and the clearance ofeach bump. For example, when the application identifies one or morepoints lacking the necessary clearance, the user may modify the designof the lens to reduce or eliminate the lack of clearance. For bumpslocated in the optic zone 502 and/or the transition zone 506, theapplication may identify one or more points having clearances below theapplicable minimum clearance thresholds, which may indicate the presenceof a bump. In order to address the bumps in these locations, theclearances at the respective points may be adjusted. For example, theinner surface of the lens may be designed with a correspondingindentation to provide the appropriate clearance at the location of thebump(s). In addition to altering the clearances, the default clearancesin the corresponding zone and/or the outer diameters of the zones can bealtered to adjust for the presence of one or more bumps.

Bumps occurring in the landing zone 508 are located, by definition, onthe sclera. The default calculation for the landing zone 508 can includea rotationally symmetrical shape. When the calculations indicate that abump exists that has less than a minimum threshold clearance, the lensdesign can be altered to account for the bump. In an embodiment, a bumpcan be taken into consideration by creating an inner lens surface thatprovides room for the bump. A bump zone can be defined by identifyingthe center of the bump. For example, the highest point of the bump maybe identified by a user or the application can automatically determinethe point having the minimum clearance. The bump zone can be representedas a circular zone (e.g., defining a dome) having a radius and a centralheight that is sufficient to provide the minimum clearance above thebump, which may be in contact with the peak of the bump. The combinationof the radius and height of the bump zone may be used to create aclearance around the bump on the sclera in the landing zone 508. Whentwo or more bumps are close together, the bump zone may cover aplurality of bumps. For example, the radius and height of the bump zonemay provide a clearance for two or more of the bumps that are sufficientclose together. The bump zone may then be placed into the lens innersurface calculation.

After computing the back surface and making any modifications for anybumps, the application may compute (e.g., automatically compute) thelens front surface in a seventh step 414. The user can define the lensmaterial refractive index, the spherical amount of the targetprescription, cylinder powers (toric design), prisms, and the lensthickness. The application can apply optical formulas to calculate thefront surface curvature in the optic zone 502, which may generallycomprise a spherical cap with any corrections for the prescription. In abottom view, the front surface in the optic zone 502 is generallycircular and has a center matching the center of the back surface of theoptic zone 502 (e.g., a centered optic zone 502 or a decentered opticzone 502). In a side view, the front surface of the optic zone 502 canhave a generally circular arc shape having a radius of curvaturesufficient to allow the lens to have a thickness between about 0.25 mmand about 0.75 mm, or between about 0.4 mm and about 0.5 mm (e.g., about0.45 mm) in the center of the optic zone 502. The lens may have adecreased thickness on the edge of the optic zone 502. In an embodiment,the lens may have a thickness between about 0.15 mm and about 0.5 mm, orbetween about 0.25 and about 0.3 mm (e.g., about 0.28 mm) on the edge ofthe optic zone 502 (e.g., at or near the border with the transition zone506). Once the optic zone 502 thickness is determined, the front surfaceshape can be altered, while maintaining the thickness at the center ofthe optic zone 502, to integrate the prescription cylinder amount. Sincethe lens cylinder power is generally less than its sphere power, theboundary thicknesses should still satisfy the predetermined thicknessthresholds after this alteration.

In an embodiment, the lens front surface calculation can calculate areduced thickness for the lens in the optic zone 502. The applicationmay initially calculate a front surface curvature in the optic zone 502.The resulting thickness of the lens in the optic zone 502 can then becalculated and checked against a predetermined thickness threshold. Ifthe front surface curvature is such that the thickness of the lens atthe boundary of the optic zone 502 is below the predetermined thicknessthresholds, the application can increases the thickness of the lens inthe center of the optic zone 502. The increased thickness can alter thecomputed front surface curvature, and therefore the resulting boundarythickness. This process may iterate until a center thickness isachieved, wherein the center thickness also satisfies the predeterminedthickness threshold, for example, at the optic zone 502 boundary withthe transition zone 506. In some embodiments, this process can be usedto find the thinnest lens thickness in the optic zone 502 that satisfiesthe predetermined thickness thresholds.

The front surface calculation for the lens in the transition zone 506can be calculated in a number of ways. The front surface of the lens inthe transition zone 506 represents a continuation of the optic zone 502,and matches the front surface of the optic zone 502 at the boundarybetween the two zones. In a bottom view, the transition zone 506 isgenerally circular and the outer border of the transition zone 506 canbe centered on the spindle axis. The inner border of the transition zone506 on the front surface is calculated to match the outer border of thefront optic zone 502. In a side view, the profile of the front surfacein the transition zone 506 is generally non-spherical in shape. Thethickness of the lens at the border between the optic zone 502 and thetransition zone 506 is described above. The lens may transition to athickness between about 0.1 mm and about 0.3 mm, or between about 0.15mm and about 0.25 mm (e.g., about 0.2 mm) at the outer border of thetransition zone 506.

The front surface calculation for the lens in the landing zone 508 canbe calculated in a number of ways. The front surface of the lens in thelanding zone 508 represents a continuation of the transition zone 506,and matching the front surface of the transition zone 506 at theboundary between the two zones. The front surface of the lens in thelanding zone 508 extends to cover both the landing zone 508 and the edgelift zone 510. Thus, the outer edge of the landing zone 508 on the frontof the lens extends to the outer edge of the lens. In a bottom view, thefront surface of the landing zone 508 has a circular, ring shape that iscentered on the spindle axis. The inner border of the ring forming thelanding zone 508 may match the back lens surface landing zone 508 innerborder, and the outer border of the ring forming the landing zone 508may match the back-surface edge lift zone 510 outer border. In a sideview, the front surface of the lens in the landing zone 508 may have anon-spherical shape. The lens may have a thickness of between about 0.1mm and about 0.3 mm, or between about 0.15 mm and about 0.25 mm (e.g.,about 0.18 mm) in the landing zone 508. The outer edge of the lens mayhave a rounded shape to avoid any sharp edges contacting the eye.

The application can calculate the front surface and then display thelens back and front surfaces in the 3D viewer to let the user see thelens. If any corrections or changes are needed, the user can modify theradius and/or thickness of any zone. In an embodiment, a user can usethe 3D presentation to verify the calculations of the lens prior tofinalizing the lens design. In general, the resulting lens designresulting from the front and back surface calculations can benon-rotationally symmetrical design. Further, the customization for eachsubject may result in a lens that may fit in a specific orientationduring use, which may allow for additional prescriptions and designsthat have not previously been achievable in a lens design.

In an eighth step 416, the back and front surfaces are then exported asa set of two data point production files, one for each surface, therebydefining the lens. Information identifying the subject may also beincluded as a separate file or within one or more of the data pointproduction files. In some embodiments, the files may be combined into asingle production file. The production files may be in a format suitablefor use in fabricating the lens, for example, suitable for use with alathe, a milling machine, and/or 3D printing machine.

The surface files can be determined by converting the computed surfacesto a set of rings centered on the spindle axis. The rings can be used tobuild 3D meshes that can be displayed in the 3D viewer as well as togenerate the production files. Viewing of the 3D surfaces allows theuser to visually check that the calculated production surfaces match thecalculated surfaces from the application.

In a ninth step 418, the lens may be fabricated using any suitablefabrication technique or method. In an embodiment, the lens may befabricated using a lathe or mill to create the lens from a lens blank.In this process, a lens blank having a suitable starting shape may beplaced in a lathe or mill. For example, a lens blank may comprise acylindrical section of lens material. In an embodiment, the lensmaterial may comprise a flexible or rigid gas permeable material (e.g.,an oxygen permeable material) suitable for use with an eye. Suitablematerials can include, but are not limited to, silicone hydrogel,silicone, a silicone derivative (e.g., a silicone acrylate), polymethylmethacrylate (PMMA), fluorosilicone acrylates, and/or any combinationthereof.

The lathe or mill may use the production file to guide the lathe or milland remove a portion of the lens blank. In order to produce a customlens, the lathe or mill may be capable of creating a non-rotationallysymmetric surface on the front, and/or back of the lens. For example, alathe may comprise an oscillating tool technology to allow non-symmetricshapes to be created in the lens. The removal of material from the lensblank may result in the formation of a lens for the subject that isspecific to the impression formed for the eye. One or more postformation processes may be used to further prepare the lens for thesubject. For example, the lens may be further polished, coated, treated,or the like to prepare it for use by a subject.

The resulting lens produced by the impression, design, and lathingprocess may provide for a number of unique properties. In an embodiment,the lens may be non-symmetric about a rotational axis. This may allowfor different curvatures in the landing zone to match the contours ofthe subject's eye. In general, the sclera is not rotationally symmetric,and the use of the impression may allow the specifics of a subject's eyeto be taken into consideration in the design of the lens.

Further, the lens may comprise non-symmetric features. For example, theoptical axis can be decentered and the lens may have features specificfor one or more bumps or other irregularities in the eye. This may bedescribed in some contexts as utilizing an X, Y, Z coordinate system,where each point on the inner and outer surface of the lens can beindependently varied. As used herein, the Z axis is parallel to thespindle axis, and the X and Y coordinate axes are aligned perpendicularto the Z axis to define a Cartesian coordinate system perpendicular tothe Z axis. In traditional lens designs, the lenses were rotationallysymmetric about the spindle axis so that at any given X and Ycoordinate, the Z coordinate was symmetric about the spindle axis. Thus,the lens described herein may have a Z coordinate that varies about thespindle axis (e.g., is non-symmetric about the spindle axis). Such alens may be described as having an independent elevation specific designin which the Z coordinate can be independently specified for each pointon the lens surface. Such a design allows for the non-symmetric designof the elements of the lens including the landing zone and any bumpzones or other features taken into consideration in the lens. Inembodiments, the Z coordinate may vary along the entire perimeter of alens.

The use of a non-symmetric lens design may allow the lens to rotate intoalignment with the features of the eye. In general, various forces suchas surface tension and interferences with the features of the eye cancreate a force that rotates the lens the proper alignment when placed onthe eye. For example, the lens may rotate until the bump zones, if any,align with the bumps on the eye. As another example, a non-symmetricdesign of the landing zone may cause the lens to rotate on the eye untilthe landing zone profile matches the scleral profile of the user. Thealignment may result in the lens rotating on the eye, which may causesome amount of blurred vision and disorientation. In order to limit orreduce the rotation of the lens, a marking or indicator can be includedon the lens to indicate an approximate starting orientation. In anembodiment, a line or dot (e.g., a colored line or dot) can be placed onthe lens to indicate the relative position of the lens when it is placedon the eye. For example, a dot may be placed in the landing zone toindicate the upwards position of the lens (e.g., the 6 o'clockposition). By aligning this marking with the upwards position whendonning the lens, the lens may be nearly aligned with the correctposition and limit the amount of rotation needed to fully align the lenswith the features of the eye. While described as being in the upwardsposition, the mark or line could be at any relative position on thelens. In an embodiment, the mark or line may be disposed on the landingzone or the edge lift zone in order to avoid interfering with the visualpath through the lens.

Once the lens has rotated to align with the features of the eye, theresulting interaction forces may keep the lens aligned on the eye. Thealignment may be maintained in the presence of rotational force. Forexample, various lens prescriptions may require that one side of thelens is thicker and/or heavier than another side. For example,prescriptions for optical prisms, astigmatism, decentered optics, aswell as other corrections may call for a lens to be unevenly weighted.For example, a lens may comprise a non-uniform thickness that creates aweighted prismatic effect with the optic zone portion of the lens. Theheaviest weighted portion of the lens may then be configured to bepositioned other than downwards when worn on the eye. In traditionallenses when the heavy side is not oriented downward, the unbalancedweight may create a rotational moment. In an embodiment, theinteractions between the asymmetric features of the lens and thefeatures on the eye may prevent the lens from rotating even in thepresence of an unbalanced weight that is not directed downwards. Thismay be referred to as being rotationally stabilized. For example, thelens may be rotationally stable on the eye when there is a weight (e.g.,due to a prism or other correction) located on a side or top of thelens. In some embodiments, the weights (e.g., due to prisms, astigmatismcorrections, high definition (HD) optics or higher order aberrations)can be located on the side or top within the optic zone of the lens inuse while the-non-rotational lens is stabilized on the eye.

The alignment may also aid in maintaining the proper vision formulti-focal optics. In general multi-focal optics allow for differentoptical powers in a single lens. Such prescriptions are typically usedto treat subject with presbyopia, myopia, hyperopia, and/or astigmatism.When present in a scleral lens, the multi-focal optics may be presentedas bands or regions in the optic zone 502 having different opticalpowers. Due to the proximity of the lens to the cornea, any minormisalignment of the lens on the eye may make it difficult for thesubject to see properly through the lens. The use of the lenses asdescribed herein may allow the lens to maintain its proper alignment onthe eye. The improved alignment and resistance to movement may improvethe ability of a subject to see out of a multi-focal lens.

When the lens has been created, it may be checked for the proper power,prescription, size, or the like. The lens can then be sent to theprescribing doctor. When the subject returns to the doctor, the lens canbe dispensed and fitted on the subject. The doctor may perform their owncheck of the lens, and typically, another vision check is performed onthe subject while the lens is being worn. If the lens is correct, thesubject may retain the lens and use the lens to correct their visionproblems. In some cases, the lens may need a minor variation in thedesign, fit, or prescription once it is dispensed by the doctor. If aminor change is needed, the doctor can send the request along with thecorrections back to the application user. Since the scan of theimpression can be maintained, a second impression is generally notneeded. Rather, the second lens can be redesigned based on the doctor'sinput, and the second lens can then be manufactured and sent to thedoctor. This process generally represents a significantly shortenedfitting process relative to other scleral lenses. The impression processcan be repeated over time (e.g., once a year) to track any changes inthe surface of the eye, if needed.

In addition to designing the lens, the impressions can be used to builda database of information for various subjects. When the impression isreceived and scanned, various information about the subject can berecorded and stored in a data store along with the 3-dimensional (3D)points (e.g., X, Y, Z coordinates) file and the resulting lens designfiles. Information about the subject can include, but is not limited to,name, date of the impression, doctor's name, birthdate, identificationof the eye belonging to the impression (e.g., OD, OS, etc.), the scanneridentification, the scanner resolution, the pathology of the subject,any notes about the subject, a patent identifier (e.g., an ID number),prescription, and any combination thereof. The data store may allow forqueries to be performed. This feature may allow a doctor to order newlenses without the need to perform an additional impression. Inaddition, the design application can begin with an existing lens designfor an existing subject rather than beginning the design process fromthe beginning.

In addition to being used for individual patients, the data store may bequeried and analyzed to determine various features of the subjectpopulation and the lens designs. Various features of the eye can beobserved by a doctor. However, the features may not be quantifiable, anda statistical analysis of a patient population may not be generallyknown. It is expected that various averages may exist for a populationof subjects needing scleral lenses. For example, the averages caninclude, but are not limited to, the average shape of the sclera, theaverage clearances needed for the lenses, the average diameters of thelimbal circle, and the like. By analyzing the data and determining oneor more averages, a standard set of lenses or lens designs could begenerated. These designs may allow for storable quantities of the lensesto be created and maintained within a storage facility. This would allowfor an off-the-shelf scleral lens to be sold to an average subject orused as a temporary lens, while allowing customized lenses to be createdfor those subjects in need of more specific modifications.

As previously discussed above, the lens may be non-symmetric about arotational axis and comprise non-symmetric features. For example, atleast some embodiments of the present disclosure provide for designingand fabricating a lens for the subject based on the mold and theresulting impression such that the lens has an asymmetric (e.g., such asoblong or egg-shaped) form in which horizontal and vertical radii arenon-equivalent (e.g., non-equal). In at least some examples, theasymmetric form is a hyperbolic paraboloid. For example, as illustratedin FIG. 6A, the lens may have a regular (e.g., geometric) non-symmetricshape in which each of the vertical radii and the horizontal radii ofthe landing zone of a lens 605 may be determined independently inrelation to the optic zone 615, limbal circle, and/or cornea 610. In oneimplementation, a radius of the temporal landing zone (t) of the lens605 is a first dimension, a radius of the vertical landing zone (v) ofthe lens 605 is a second dimension, a radius of the nasal landing zone(n) of the lens 605 is a third dimension, and a radius of the inferiorlanding zone (i) of the lens 605 is a fourth dimension, where at leastsome of the first dimension, second dimension, third dimension, andfourth dimension are different from a remainder of the first dimension,second dimension, third dimension, and fourth dimension. In one example,a radius of the temporal landing zone of the lens 605 is about 8 mm, aradius of the vertical landing zone of the lens is about 4 mm, a radiusof the nasal landing zone of the lens is about 3 mm, and a radius of theinferior landing zone of the lens is about 5 mm. As further illustratedin FIG. 6B, the lens 605 may have an irregular (e.g., non-geometric)non-symmetric shape, for example, to provide for an improved fit to thesubject's eye and/or to provide for specific desired manipulations, asdiscussed in further detail below.

In at least one example, varying one or more of the radii of thetemporal landing zone in relation to the optic zone, limbal circle,and/or cornea may provide for a uniform landing zone with respect tooptic zone, limbal circle, and/or cornea. For example, a dimension ofone or more of the radii of the temporal landing zone is varied inrelation to the optic zone, limbal circle, and/or cornea such that thelanding zone extends an approximately equal distance from the opticzone, limbal circle, and/or cornea in each direction (e.g., horizontaland vertical radii directions). The approximate uniformity of thedistance of the landing zone from the optic zone, limbal circle, and/orcornea may increase rotational stability of the lens. The variation andthe resulting increased rotational stability may improve a fit of thelens to the subject's eye and/or an optical improvement caused by thelens for the subject. For example, the increased rotational stabilitymay enable correction of higher order aberrations of the subject byincreasing a prevision of an alignment of the visual axis of the lenswith the visual axis of the subject and/or applying higher orderaberration corrections.

In another example, the lens may be extended in one or more dimensions agreater distance than in one or more other dimensions such that thelanding zone extends varying distance from the optic zone, limbalcircle, and/or cornea in at least one direction. For example, a temporalradius of the lens may be increased. The lens may be further manipulatedin the area resulting from extended temporal radius, or in any otherareas that do not overlap the subject's cornea. The manipulation mayinclude correction for cosmetic abnormalities of the subject (e.g.,artificially coloring a portion of the lens to correct for adiscolorment or deformity in the subject's eye), the inclusion of aninsignia, decoration, logo, or other aesthetic element, the inclusion ofelectronics or embedded devices (e.g., a camera, sensors, etc.), or anyother suitable manipulation of the lens outside of the cornea.

Turning now to FIG. 7, and as additionally discussed above, the opticalzone (e.g., the optical axis) may be de-centered from the spindle axis,visual axis, or both. In at least some examples, this de-centeringincludes both a back lens surface optical zone 705 and a front lenssurface optical zone 710. In some examples, the back lens surfaceoptical zone 705 and the front lens surface optical zone 710 are linked(e.g., such that a movement to one causes a corresponding movement tothe other), while in other examples the back lens surface optical zone705 is de-coupled from the front lens surface optical zone 710 (e.g.,such that each is independently repositionable). De-coupling a positionof the back lens surface optical zone 705 from a position of the frontlens surface optical zone 710, in at least some examples, facilitatescorrection of higher order aberrations in the subject's eyes and/orvision, as discussed above. For example, by de-coupling the position ofthe back lens surface optical zone 705 from dependence on the positionof the front lens surface optical zone 710, corrective powers of thelens 715 may be aligned to a point of vision of the subject's eye 720 asopposed to a central optical zone diameter of the lens 715 based on itsposition when seated on the subject's eye 720. In this way, the backlens surface optical zone 705 and the front lens surface optical zone710 may each be aligned over the visual center of a subject's eye 720 asopposed to geometric centers of the optical zones and/or pupil areas ofthe subject's eye 720. In another example, the back lens surface opticalzone 705 and the front lens surface optical zone 710 may beindependently de-centered and positioned to create separate (sometimesunrelated) results. For example, the front lens surface optic zone 710may be de-centered and positioned according to considerations ofcorrective power and/or optics and the back lens surface optic zone 705may be de-centered and positioned according to considerations of a fitof the lens to the subject's eye 720.

Turning now to FIG. 8, various aspects of the systems described hereinmay be executed on a processor, for example, a processor in a computersystem 800. For example, the design process including scanning theimpression and designing the lens as well as various components of thelens manufacturing process may be implemented on a computer and/or theprocessor on a computer. FIG. 8 illustrates a computer system 800suitable for implementing one or more of the embodiments of theseprocesses as disclosed herein. The computer system 800 includes aprocessor 802 (which may be referred to as a central processor unit orCPU) that is in communication with memory devices including secondarystorage 804, read only memory (ROM) 806, random access memory (RAM) 808,input/output (I/O) devices 810, and network connectivity devices 812.The processor 802 may be implemented as one or more CPU chips.

It is understood that by programming and/or loading executableinstructions onto the computer system 800, at least one of the CPU 802,the RAM 808, and the ROM 806 are changed, transforming the computersystem 800 in part into a particular machine or apparatus having thenovel functionality taught by the present disclosure. It is fundamentalto the electrical engineering and software engineering arts thatfunctionality that can be implemented by loading executable softwareinto a computer can be converted to a hardware implementation bywell-known design rules. Decisions between implementing a concept insoftware versus hardware typically hinge on considerations of stabilityof the design and numbers of units to be produced rather than any issuesinvolved in translating from the software domain to the hardware domain.Generally, a design that is still subject to frequent change may bepreferred to be implemented in software, because re-spinning a hardwareimplementation is more expensive than re-spinning a software design.Generally, a design that is stable that will be produced in large volumemay be preferred to be implemented in hardware, for example in anapplication specific integrated circuit (ASIC), because for largeproduction runs the hardware implementation may be less expensive thanthe software implementation. Often a design may be developed and testedin a software form and later transformed, by well-known design rules, toan equivalent hardware implementation in an application specificintegrated circuit that hardwires the instructions of the software. Inthe same manner as a machine controlled by a new ASIC is a particularmachine or apparatus, likewise a computer that has been programmedand/or loaded with executable instructions may be viewed as a particularmachine or apparatus.

The secondary storage 804 is typically comprised of one or more diskdrives or tape drives and is used for non-volatile storage of data andas an over-flow data storage device if RAM 808 is not large enough tohold all working data. Secondary storage 804 may be used to storeprograms, which are loaded into RAM 808 when such programs are selectedfor execution. The ROM 806 is used to store instructions and perhapsdata, which are read during program execution. ROM 806 is a non-volatilememory device, which typically has a small memory capacity relative tothe larger memory capacity of secondary storage 804. The RAM 808 is usedto store volatile data and perhaps to store instructions. Access to bothROM 806 and RAM 808 is typically faster than to secondary storage 804.The secondary storage 804, the RAM 808, and/or the ROM 806 may bereferred to in some contexts as computer readable storage media and/ornon-transitory computer readable media.

I/O devices 810 may include printers, video monitors, liquid crystaldisplays (LCDs), touch screen displays, keyboards, keypads, switches,dials, mice, track balls, voice recognizers, card readers, paper tapereaders, or other well-known input devices.

The network connectivity devices 812 may take the form of modems, modembanks, Ethernet cards, universal serial bus (USB) interface cards,serial interfaces, token ring cards, fiber distributed data interface(FDDI) cards, wireless local area network (WLAN) cards, radiotransceiver cards such as code division multiple access (CDMA), globalsystem for mobile communications (GSM), long-term evolution (LTE),worldwide interoperability for microwave access (WiMAX), and/or otherair interface protocol radio transceiver cards, and other well-knownnetwork devices. These network connectivity devices 812 may enable theprocessor 802 to communicate with an Internet or one or more intranets.With such a network connection, it is contemplated that the processor802 might receive information from the network, or might outputinformation to the network in the course of performing theabove-described method steps. Such information, which is oftenrepresented as a sequence of instructions to be executed using processor802, may be received from and outputted to the network, for example, inthe form of a computer data signal embodied in a carrier wave.

Such information, which may include data or instructions to be executedusing processor 802 for example, may be received from and outputted tothe network, for example, in the form of a computer data baseband signalor signal embodied in a carrier wave. The baseband signal or signalembodied in the carrier wave generated by the network connectivitydevices 812 may propagate in or on the surface of electrical conductors,in coaxial cables, in waveguides, in an optical conduit, for example anoptical fiber, or in the air or free space. The information contained inthe baseband signal or signal embedded in the carrier wave may beordered according to different sequences, as may be desirable for eitherprocessing or generating the information or transmitting or receivingthe information. The baseband signal or signal embedded in the carrierwave, or other types of signals currently used or hereafter developed,may be generated according to several methods well known to one skilledin the art. The baseband signal and/or signal embedded in the carrierwave may be referred to in some contexts as a transitory signal.

The processor 802 executes instructions, codes, computer programs,scripts which it accesses from hard disk, floppy disk, optical disk(these various disk based systems may all be considered secondarystorage 804), ROM 806, RAM 808, or the network connectivity devices 812.While only one processor 802 is shown, multiple processors may bepresent. Thus, while instructions may be discussed as executed by aprocessor, the instructions may be executed simultaneously, serially, orotherwise executed by one or multiple processors. Instructions, codes,computer programs, scripts, and/or data that may be accessed from thesecondary storage 804, for example, hard drives, floppy disks, opticaldisks, and/or other device, the ROM 806, and/or the RAM 808 may bereferred to in some contexts as non-transitory instructions and/ornon-transitory information.

In an embodiment, the computer system 800 may comprise two or morecomputers in communication with each other that collaborate to perform atask. For example, but not by way of limitation, an application may bepartitioned in such a way as to permit concurrent and/or parallelprocessing of the instructions of the application. Alternatively, thedata processed by the application may be partitioned in such a way as topermit concurrent and/or parallel processing of different portions of adata set by the two or more computers. In an embodiment, virtualizationsoftware may be employed by the computer system 800 to provide thefunctionality of a number of servers that is not directly bound to thenumber of computers in the computer system 800. For example,virtualization software may provide twenty virtual servers on fourphysical computers. In an embodiment, the functionality disclosed abovemay be provided by executing the application and/or applications in acloud computing environment. Cloud computing may comprise providingcomputing services via a network connection using dynamically scalablecomputing resources. Cloud computing may be supported, at least in part,by virtualization software. A cloud computing environment may beestablished by an enterprise and/or may be hired on an as-needed basisfrom a third party provider. Some cloud computing environments maycomprise cloud computing resources owned and operated by the enterpriseas well as cloud computing resources hired and/or leased from a thirdparty provider.

In an embodiment, some or all of the functionality disclosed above maybe provided as a computer program product. The computer program productmay comprise one or more computer readable storage medium havingcomputer usable program code embodied therein to implement thefunctionality disclosed above. The computer program product may comprisedata structures, executable instructions, and other computer usableprogram code. The computer program product may be embodied in removablecomputer storage media and/or non-removable computer storage media. Theremovable computer readable storage medium may comprise, withoutlimitation, a paper tape, a magnetic tape, magnetic disk, an opticaldisk, a solid state memory chip, for example analog magnetic tape,compact disk read only memory (CD-ROM) disks, floppy disks, jump drives,digital cards, multimedia cards, and others. The computer programproduct may be suitable for loading, by the computer system 800, atleast portions of the contents of the computer program product to thesecondary storage 804, to the ROM 806, to the RAM 808, and/or to othernon-volatile memory and volatile memory of the computer system 800. Theprocessor 802 may process the executable instructions and/or datastructures in part by directly accessing the computer program product,for example by reading from a CD-ROM disk inserted into a disk driveperipheral of the computer system 800. Alternatively, the processor 802may process the executable instructions and/or data structures byremotely accessing the computer program product, for example bydownloading the executable instructions and/or data structures from aremote server through the network connectivity devices 812. The computerprogram product may comprise instructions that promote the loadingand/or copying of data, data structures, files, and/or executableinstructions to the secondary storage 804, to the ROM 806, to the RAM808, and/or to other non-volatile memory and volatile memory of thecomputer system 800.

In some contexts, a baseband signal and/or a signal embodied in acarrier wave may be referred to as a transitory signal. In somecontexts, the secondary storage 804, the ROM 806, and the RAM 808 may bereferred to as a non-transitory computer readable medium or a computerreadable storage media. A dynamic RAM embodiment of the RAM 808,likewise, may be referred to as a non-transitory computer readablemedium in that while the dynamic RAM receives electrical power and isoperated in accordance with its design, for example during a period oftime during which the computer 800 is turned on and operational, thedynamic RAM stores information that is written to it. Similarly, theprocessor 802 may comprise an internal RAM, an internal ROM, a cachememory, and/or other internal non-transitory storage blocks, sections,or components that may be referred to in some contexts as non-transitorycomputer readable media or computer readable storage media.

At least one embodiment is disclosed and variations, combinations,and/or modifications of the embodiment(s) and/or features of theembodiment(s) made by a person having ordinary skill in the art arewithin the scope of the disclosure. Alternative embodiments that resultfrom combining, integrating, and/or omitting features of theembodiment(s) are also within the scope of the disclosure. Wherenumerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4,etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example,whenever a numerical range with a lower limit, R_(l), and an upperlimit, R_(u), is disclosed, any number falling within the range isspecifically disclosed. In particular, the following numbers within therange are specifically disclosed: R=R_(l)+k*(R_(u)−R_(l)), wherein k isa variable ranging from 1 percent to 100 percent with a 1 percentincrement, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5percent, . . . , 50 percent, 51 percent, 52 percent, . . . , 95 percent,96 percent, 97 percent, 98 percent, 99 percent, or 100 percent.Moreover, any numerical range defined by two R numbers as defined in theabove is also specifically disclosed. Use of the term “about” means±10percent of the subsequent number. Use of the term “optionally” withrespect to any element of a claim means that the element is required, oralternatively, the element is not required, both alternatives beingwithin the scope of the claim. Use of broader terms such as comprises,includes, and having should be understood to provide support fornarrower terms such as consisting of, consisting essentially of, andcomprised substantially of. Accordingly, the scope of protection is notlimited by the description set out above but is defined by the claimsthat follow, that scope including all equivalents of the subject matterof the claims. Each and every claim is incorporated as furtherdisclosure into the specification and the claims are embodiment(s) ofthe present invention.

What is claimed is:
 1. A method of creating a lens, comprising:identifying a limbal zone of the eye; determining a back optic zonewithin the limbal zone; determining a front optic zone based at leastpartially on the limbal zone; computing a lens surface of the lens basedat least partially on the limbal zone, the back optic zone, and thefront optic zone; and de-centering at least one of the back optic zoneor the front optic zone from a visual axis or a spindle axis of thelens.
 2. The method of claim 1, wherein de-centering the back optic zonerepositions the back optic zone without repositioning the front opticzone.
 3. The method of claim 1, wherein de-centering the front opticzone repositions the front optic zone without repositioning the backoptic zone.
 4. The method of claim 1, wherein de-centering at least oneof the back optic zone or the front optic zone aligns the back opticzone and the front optic zone with a point of vision of the eye.
 5. Themethod of claim 1, wherein de-centering at least one of the back opticzone or the front optic zone aligns the back optic zone and the frontoptic zone with a visual center of the eye.
 6. The method of claim 1,wherein a position of the back optic zone is de-coupled from dependenceon a position of the front optic zone.
 7. The method of claim 1, furthercomprising instructing a manufacturing apparatus to fabricate the lensby manipulating a lens material according to the design for the lens. 8.The method of claim 1, further comprising: obtaining digital informationrepresentative of the eye, the digital information including a pluralityof data points each associated with elevation specific information;generating an elevation map according to the elevation specificinformation; and determining a level of irregularity of the subject'seye according to the elevation map.
 9. A method of creating a lens,comprising: determining characteristics of a back lens surface includinga back optic zone; and determining characteristics of a front lenssurface including a front optic zone, wherein a position of the backoptic zone is de-coupled from dependence on a position of the frontoptic zone.
 10. The method of claim 9, wherein at least one of the backoptic zone or the front optic zone is de-centered from a spindle axis ofthe lens.
 11. The method of claim 9, wherein at least one of the backoptic zone or the front optic zone is de-centered from a visual axis ofthe lens.
 12. The method of claim 9, wherein one of the back optic zoneor the front optic zone is repositioned without repositioning the otherof the back optic zone or the front optic zone.
 13. The method of claim9, wherein one of the back optic zone or the front optic zone is alignedwith a point of vision of a subject's eye.
 14. The method of claim 9,wherein one of the back optic zone or the front optic zone is alignedwith a visual center of a subject's eye.
 15. The method of claim 9,further comprising instructing a manufacturing apparatus to fabricatethe lens by manipulating a lens material according to the design for thelens.
 16. A lens, comprising: a back optic zone; a front optic zone; anda lens surface determined at least partially based on the back opticzone and the front optic zone, wherein at least one of the back opticzone or the front optic zone is de-centered from a visual axis or aspindle axis of the lens.
 17. The lens of claim 16, wherein a positionof the back optic zone is de-coupled from dependence on a position ofthe front optic zone.
 18. The lens of claim 16, wherein one of the backoptic zone or the front optic zone is repositioned without repositioningthe other of the back optic zone or the front optic zone.
 19. The lensof claim 16, wherein one of the back optic zone or the front optic zoneis aligned with a visual center of a subject's eye.
 20. The lens ofclaim 16, wherein one of the back optic zone or the front optic zone isaligned with a point of vision of a subject's eye.